The invention relates to the field of reproduction technology and is directed to a device for the deflection of an optical beam, said device being composed of at least one prism that is provided with at least one reflection face and is rotationally seated with respect to a rotational axis.
Light beam deflection devices are employed, for example, in scanner elements for originals scanner devices or in recording elements for recording devices.
In an originals scanner device, also referred to as an input scanner, a light beam generated in a scanner element is conducted point-by-point and line-by-line across an original to be scanned, and the scan light reflected from or transmitted through the original is converted into an image signal in an optoelectronic transducer. In a recording device, also referred to as a recorder, an exposer or an output scanner, the light beam acquired in a recording element is intensity modulated by an image signal for recording information and is conducted point-by-point and line-by-line across a light-sensitive recording material.
In the case of a flat bed apparatus, the holder for the original or for the recording material is a planar surface over which the light beam is conducted point-by-point and line-by-line, and that moves relative to the scanner element or the recording element. In the case of an inside drum apparatus, the holder for the original or for the recording material is designed as a stationary half-shell or trough. The scanner element or recording element moves parallel to the longitudinal axis of the halfshell or trough, and the light beam is conducted radially across the original or the recording material perpendicularly relative to the longitudinal axis.
DE-C-39 18 075 discloses such a light beam deflection means having a prism. An incident light beam here is first introduced into the prism via a light entry face and is inwardly reflected in the region of an exit face. Another reflection occurs at a further limiting face, and the light beam is refracted upon exit of the light beam from the prism. The prism has an asymmetrical mass distribution with respect to the rotational axis which, due to the flying forces arising upon rotation of the light beam deflection means, only allows a limited speed range. Over and above this, considerable air turbulences that can cause noise and contamination occur at higher speeds as a consequence of a shaping that is asymmetrical with respect to the rotational axis.
Another light beam deflection means comprising a prism is disclosed by U.S. Pat. No. 4,878,720. Here, too, the prism has a shaping as well as a mass distribution with respect to the rotational axis which lead to considerable, asymmetrical centrifugal forces as well as to a creation of noise.